Glasses and distortions.. (1 Viewer)

[Yippeekiay]

Just wondering how many pairs of bin's have been passed on because the owner didn't take the possibility of his eye glasses creating some aberration or another into account.
The reason I ask is a recent experience where it's quite possible that the edge distortion in my Fujinon's may have been the result of my prescription glasses.
I took a shot and tried them with my contact lenses and it seems to have eliminated some of the problem. No extensive tests were done but there did seem to be some improvement. Gonna have to sit down and figure this one out.

Until then I still have to wonder if this has been discussed before.

 

[newfie ghost]

This is a great point yippee. Most eye glasses have wicked distortion and ca. Going naked is a better test.:-O

 

[John Dracon]

Have wondered the same thing as an eye glass wearer, particularly since mine are for correcting astigmatism, which binoculars won't do. Also, more glass surfaces reduce light passage. Perhaps we eye glass wearers with astigmatism simply must resign ourselves to less than than the optimum view.
John

 

[elkcub]

I'm an eyeglass wearer with astigmatism who finds the view wonderfully optimized using glasses. In fact, as noted on other threads, I much prefer viewing with photochromic eyeglasses that modulate brightness, and which also allow for peripheral vision. Much of this, I admit, may be due to Swarovski's superb design of the 8x42 SLC HD, which is well baffled, minimizes side reflections, and has 18.5mm eye relief. Also consider that the only eyeglass aberrations that might matter come from the small central area in front of the exit pupil.

At least that's how I see it. o
Ed

 

[looksharp65]

It is true that spectacles induce various size and shape distortions, prism effects and CA, but like Ed I doubt that would be visible through the very small central zone resembling the exit pupil.

In fact, I find it appalling that there are so many fine binoculars out there whose true performance is unused due to the poor eyesight of the owners.
Some of them don't even know that they can screw in the eyecup :-O.

An important advantage of using spectacles with binoculars is that you are free from the hassle of taking them off and holding them in your hand while using the bins.

So, what are the disadvantages then?

1) Some people are distracted by the extended peripheral view and disturbing side-light. (For me, however, the PFOV is a desirable property of good binoculars)

2) When the eyecups are not extended and rest on the lenses of one's spectacles, eye placement is more critical. With the eyecups extended, they will fit into your eye sockets and provide a rough and immediate guide for the eye placement.
Furthermore, the IPD adjustment may need to change a little and this is more difficult for the same reason.
I believe this eye placement/IPD thing is the most obvious cause that binoculars don't seem to deliver as expected when used with spectacles.

3) The eye relief changes. Here, I mean the actual distance between the eye end the instrument, not the property of the instrument, which I'd like to call "Maximum eye relief in millimeters".
With some binoculars, the best optical performance will be obtained at a shorter eye relief than spectacle use admits. With others, a longer eye relief will get the best out of the binoculars.

As an example, I remember that I once used my Fury 6.5x32 when I wore contacts, and they showed significantly more CA than when I use them with spectacles.

//L

 

[newfie ghost]

I get the best views with glasses as compared to contacts but since I have astigmatism it is on axis only. Look way from center then the distortions brew with glasses. Oddly enough, I get better views with no glasses as compared to contacts.

 

[John Dracon]

Ed - I can recall when I didn't need glasses. Then binoculars gave me a much better view. But we have no argument here. Everyone sees differently with or without glasses,
John

 

[elkcub]

John,

I'm curious about the binoculars you use and the eye relief.

Ed